1. Volume 24, Issue 1, Pages 130-137 (July 2013)
Platelet-Derived Nucleotides Promote Tumor-Cell Transendothelial Migration and Metastasis via P2Y2 Receptor 
Dagmar Schumacher, Boris Strilic, Kishor Kumar Sivaraj, Nina Wettschureck, Stefan Offermanns 
Cancer Cell 
Volume 24, Issue 1, Pages (July 2013)
DOI: /j.ccr
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2. Cancer Cell 2013 24, 130-137DOI: (10.1016/j.ccr.2013.05.008)
Copyright © 2013 Elsevier Inc. Terms and Conditions

3. Figure 1
Platelets Stimulate Tumor Cell Transmigration In Vitro through Release of Nucleotides
(A and B) The indicated murine tumor cells were seeded on murine MS1 microvascular endothelial cells, and tumor cell transmigration was determined in the absence or presence of platelets (± Plts) (A) or supernatants (supernat.) of platelets preincubated in the absence (− stim.) or presence of tumor cells (+ stim.) (B) (n = 5).
(C) Effect of the COX-inhibitor flurbiprofen (Flurbipr., 100 nM) or the ATP/ADP-degrading enzyme apyrase (Apyr., 20 U/ml) on platelet (Plts)-dependent stimulation of B16 cell transendothelial migration (n = 5).
(D) Release of ATP from platelets (Plts) alone, B16 cells (TC) alone, or a mixture of tumor cells and platelets (1:100) in the absence or presence of apyrase (Apyr., 20 U/ml).
(E) Effect of the stable ATP analog ATPγS (10 μM) on transendothelial migration of B16 cells (n = 5).
(F) Effect of B16 cells (TC) and platelets (Plts) alone or together in the absence and presence of apyrase (Apyr., 20 U/ml) on the permeability of an MS1 endothelial cell layer as determined by permeability for FITC-dextran (n = 5).
(G and H) Morphology of MS1 endothelial cells exposed to supernatants from B16 cells alone or B16 cells incubated with platelets (Plts) in the absence and presence of apyrase (Apyr.). Cells were stained for vascular endothelial-cadherin (red), F-actin (green), and cell nuclei (blue). The percentage of discontinuous cellular junctions was determined (G) (n = 4). Boxes in (H) indicate enlarged areas at the bottom. Bar length: 5 μm. Shown are mean values ± SD (D and G) or SEM (A–C, E, and F); ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p <
See also Figure S1.
Cancer Cell  , DOI: ( /j.ccr )
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4. Figure 2
Loss of Dense Granule Secretion Blocks Platelet-Mediated Tumor Cell Transmigration In Vitro
(A–F) Effect of thrombin (A, C, and E) or tumor cells (B, D, and F) on release of PF4 (A and B), vWF (C and D), or ATP (E and F) from wild-type (WT), Munc13-4-deficient platelets (KO) (n = 3–5), or in the absence of platelets (− Plts).
(G) Effect of WT and Munc13-4-deficient platelets (KO) on transendothelial migration of B16 (left panel) and LLC1 tumor cells (right panel) (n = 5). Shown are mean values ± SD (A–F) or SEM (G); ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p < 0.001; n.s., not significant.
See also Figure S2.
Cancer Cell  , DOI: ( /j.ccr )
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5. Figure 3
Reduced Tumor Cell Metastasis in Mice with Defective Dense Granule Secretion
(A–D) B16 (A and C) or LLC1 cells (B and D) were injected subcutaneously in the flank of WT or Munc13-4-deficient mice (KO). After 21 days, animals were sacrificed, primary tumor weight was determined (A and B), and lungs of animals were histologically analyzed for the occurrence of metastases. Total number as well as the number of small (diameter: <0.1 mm), medium-sized (diameter: 0.1–1.0 mm), or large (diameter: >1.0 mm) lung metastases was determined (n = 7–10) (C and D).
(E and F) B16 (E) or LLC1 cells (F) were injected i.v. into WT or Munc13-4-deficient mice (KO), and 12 days later, lung metastases were evaluated as in (B) and (D) (n = 6–10). The images show representative lung surface metastases (E) or stained lung sections (F) from WT or Munc13-4-deficient mice (KO). Bar length: 100 μm. Arrowheads indicate metastases. Shown are mean values ± SD; ∗p < 0.05; ∗∗p < 0.01.
See also Figure S3.
Cancer Cell  , DOI: ( /j.ccr )
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6. Figure 4
Platelet-Mediated Facilitation of Tumor Cell Extravasation and Metastasis Involves P2Y2 Receptors
(A) Effect of the P2X4 receptor antagonist 5-BDBD (1 μM) and of the P2Y1 antagonist MRS2500 (100 nM) on platelet-stimulated transendothelial migration of B16 cells (n = 5).
(B) Endothelial cells were transfected with control siRNA or with siRNAs directed against the messenger RNAs encoding P2Y1, P2Y2, or P2X4. Thereafter, transmigration of B16 cells was determined in the absence or presence of platelets (± Plts) (n = 5).
(C and D) FITC-dextran extravasation in the lungs of WT, Munc13-4-deficient (Munc13-4 KO), or P2Y2-deficient (P2Y2 KO) mice 3 hr after i.v. injection of buffer or B16 cells. Shown in (C) are representative images of lung sections stained for CD31 (red) or cell nuclei (blue). Extravasation sites of FITC-dextran (FITC-DX; green) are indicated by arrowheads; bar length: 10 μm. The bar diagram (D) shows a quantification of extraluminal FITC-positive sites (n = 4).
(E and F) Extravasation of CFSE-labeled B16 cells in the lungs of WT, Munc13-4-deficient (Munc14-3 KO), or P2Y2-deficient (P2Y2 KO) mice 6 hr after i.v. injection. Shown are, in (E), representative images of lung sections stained for CD31 (red) or cell nuclei (blue); B16 cells are in green; bar length: 10 μm. The numbers of extravasating tumor cells per 10 mm2 area of sectioned lung surface are shown in (F) (n = 9–10).
(G and H) B16 (G) and LLC1 cells (H) were injected i.v. in WT and P2Y2-deficient mice (KO), and 12 days later, lung metastases were analyzed histologically (n = 7–10). Shown are mean values ± SD (G and H) or SEM (A, B, D, and F); ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p < 0.001; n.s., not significant.
See also Figure S4.
Cancer Cell  , DOI: ( /j.ccr )
Copyright © 2013 Elsevier Inc. Terms and Conditions